ELECTRICAL SAFETY

MICHAEL BOWMAN
 ELECTRICAL SAFETY
What is electrical safety?

Electrical safety is the practice of recognizing and taking the action steps
necessary for being in the presence of electrical energy.

We rely on electricity, but sometimes underestimate its capability of

causing injury. Even household current (120 volts) can stop your heart.
Persons need to be aware of the hazards electricity poses, such as shock,
fire and explosion, and either eliminate or control those hazards.
 Electric Shock

Electrical shock happens when current passes through the

body. Electricity travels through closed circuits, and people,
sometimes tragically, can become part of the circuit. When a
person receives a shock, electricity flows between parts of the
body or through the body to a ground. This can happen if
someone touches both wires of an energized circuit, touches
one wire of the circuit while standing unprotected or touches a
metal part that has become energized.
 Electrocution
Electrocution refers to the injury or lethal dose of electrical
energy. Electricity can also cause forceful muscle contraction or
falls. The severity of injury depends on the amount of current
flowing through the body, the current's path through the body,
the length of time the body remains in the circuit and the
current's frequency.
 Fire/Explosion
• Electrical fires may be caused by excessive resistance that generates
heat from any of the following:
• Too much current running through wiring where overcurrent protection
fails or does not exist
• Faulty electrical outlets resulting in poor contact or arcing
• Poor wiring connections and old wiring that is damaged and cannot
support the load
• An explosion can occur when electricity ignites a flammable gas or
combustible dust mixture in the air. Ignition from a short circuit or static
charge is possible.
 Electrical Safety Basics
• Don't work with exposed conductors carrying 50 volts or more.
• Make sure electrical equipment is properly connected, grounded and in good
working order.
• Extension cords may not be used as permanent wiring and should be removed after
temporary use for an activity or event.
• Surge suppressors with built-in circuit breakers may be used long-term and are
available with three, six and 15 foot-long cords.
• High amperage equipment such as space heaters, portable air conditioners and
other equipment must be plugged directly into permanent wall receptacles.
• Do not access, use or alter any building’s electrical service, including circuit breaker
panels, unless you are specifically qualified and authorized to do so.
• Wet environments can increase the risk of an electrical shock.
 ELECTRICAL SAFETY
• Within this industry, you may be involved in a range of work activities
such as using measuring instruments, soldering, using hand, power and
specialist tools and constructing circuits.
• Only licensed electrical workers can legally perform electrical work.
• This includes new electrical installations and alterations, and repairs to
existing installations. An unqualified person must not be employed or
allowed to undertake electrical work.
• Apprentices and trainees must be supervised by a qualified electrical
worker at all times.
• Your employer must make sure you are properly trained and supervised,
that you are instructed in safe work procedures, and that all equipment
is in good working order.
 Grounding

To prevent electrical hazards, always make sure equipment

is properly grounded. Electrical grounding provides an
alternate path for electricity to follow, rather than going
through a person. Equipment with a grounding prong must
be plugged into an extension cord with a ground; the
grounding plug should not be removed from the equipment.

The grounding conductor is also called the protective

conductor.
 Wet Locations
For this standard wet location can be defined as an area
that is either permanently or intermittently moist or wet.

When using electricity in a wet or damp location, including

outdoor locations, a Ground Fault Circuit Interrupter (GFCI)
must be used. The GFCI ensures that any electrical shock
is brief. Although painful, it wouldn’t be fatal because the
GFCI creates a ground fault or leak in the current.
 Ground-Fault Circuit Interrupter
A ground-fault circuit interrupter (GFCI) is the only
protection device designed to protect people against
electric shock from an electrical system. Because of this,
we need to understand what a GFCI is, how it works, and
what its limitations are. We need only to look to the NEC for
the definition of a GFCI.
 Ground-Fault Circuit Interrupter
A ground fault circuit interrupter (GFCI), or Residual Current
Device (RCD) is a type of circuit breaker which shuts off electric
power when it senses an imbalance between the outgoing and
incoming current. ... A circuit breaker protects the house wires
and receptacles from overheating and possible fire.
An RCD, or residual current device, is a life-
saving device which is designed to prevent you from getting a
fatal electric shock if you touch something live, such as a bare
wire. ... RCDs offer a level of personal protection that ordinary
fuses and circuit-breakers cannot provide.
PREVENTION OF ACCIDENTS
• Main Causes of Accidents
• Carelessness – When a job is done often enough it gets boring and boredom causes
careless work. e.g. a maintenance electrician may continually check control
equipment when it is live and become unconscious of the danger. Don’t let
familiarity breed contempt.

• Ignorance – Accidents often occur in industry due to the ignorance or inexperience

of workers. Remember that most tasks look easy when done by an expert. Do not
attempt a difficult job unless under supervision.

• Skylarking – Skylarking can often lead to serious and sometimes, fatal accidents in a
factory or workshop.
 Sources of Danger
• Portable Equipment and Tools –portable equipment is one of the greatest single
causes of serious accidents in an electrical installation
• Effectiveness of earth continuity conductor. – This should be regularly checked.
• Water and Chemicals – Moisture impregnates insulation and is often the cause
of breakdown. Portable tools should be handled with great care especially in
atmospheres containing inflammable chemicals
• Temporary Installations – These are common sources of electrical accidents
• Uses of cable without mechanical protection
• Lack of protective covering on switches ,boxes etc.
• Cable run over sharp edges
• Use of unearthed brass or un-skirted lamp holders
• Unauthorised additions to circuits resulting overload.
• Circuits over-fused
 Other Sources of Danger
• Unprotected electric heaters
• Over-loaded or over fused cables, particularly flexes
• Unprotected or unearthed socket outlets
• Poor or broken earth connections leading to live metalwork under fault conditions.

Points of Danger for the Electrician

1. Burns – Electrical burns are more dangerous than normal burns as they are usually
caused by arc containing molten metal.
2. Falls- a very large number of industrial accidents are caused by falls
3. Ladders –below are some very important points to note about ladders
• Ladders should always be placed at a reasonable angle to the vertical
• Ladders should be anchored on a non slip surface or effectively wedged.
• Aluminium ladders should be used with great caution especially near conductors
• Do not attempt to lift heavy equipment up or down a ladder.
• Do not attempt acrobatics on a ladder
4. Strains – Strains occur in attempts to lift heavy weights or by lifting weights
incorrectly.

5. Electric Shock – This is one of the main hazards in our craft. See below
certain precautions that should be taken:
• Never assume that a n installation is “dead”; check thoroughly before opening equipment and
DO NOT check by touching conductors with your fingertips
• If working on an installation to which other people have access, remove fuses and keep them
besides you.

6. Moving Machinery – Great care should be taken when working on moving

machinery; oil rags and tags should be kept well clear. Do not remove guards, if it
is necessary to remove a guard, do so when the machine is stationary. Replace
all guards before leaving a machine

Googles should always be warn when operating a grinder and particular care
should be taken when drilling and grinding soft metals. (e.g. brass and copper)
 Personal protective equipment (PPE)
Personal protective equipment (PPE) is protective
clothing, helmets, goggles, or other garments or equipment
designed to protect the wearer's body from injury or
infection. The hazards addressed by protective equipment
include physical, electrical, heat, chemicals, biohazards,
and airborne particulate matter.
 Personal protective equipment (PPE)
• coveralls and protective aprons
• protective headgear - safety helmets
• safety boots or shoes
• safety glasses or goggles
• gloves
• respirators and masks
• earmuffs and earpieces
• Harness
 Protective coveralls
Protective coveralls were created to ensure a high level
of protection during work activities. They cover or replace
personal clothing and their main purpose is to protect the
worker from chemical, biological, mechanical, thermal,
electromagnetic and electrical hazards
Protective coveralls
 Safety Helmets

A hard hat is a type of helmet predominantly used in workplace

environments such as industrial or construction sites to protect the
head from injury.
 Safety Shoes
A pair of safety shoes (also known as safety boots) is personal protective
equipment (PPE) for foot protection at workplaces. It prevents from getting foot
injuries
 Safety Glasses
Special pieces of strong glass or plastic in a frame that fits tightly to
a person's face to protect their eyes from dangerous chemicals or
machines.
 Safety Glove
A safety glove is designed to keep you safe from hazards including cuts,
chemical burns, abrasion, crushing or contact with bio-hazards. Safety glove is
really just another name for work glove. But choosing the right style
of gloves is what really matters.
 Respirators and Masks

A dust mask is a flexible pad held over the nose and mouth by elastic or rubber
straps to protect against dusts encountered during construction or cleaning
activities, such as dusts from drywall, brick, wood, fiberglass, silica, etc

A respirator is a device designed to protect the wearer from inhaling hazardous

atmospheres, including particulate matter such as dusts and airborne
microorganisms, as well as hazardous fumes, vapours and gases.
Respirators and Masks
 Safety Earmuffs and Earpieces
Ear muffs fit over the ears to protect against potentially harmful
sound levels that can cause hearing loss
 Safety Harness
A safety harness is a form of protective equipment designed to protect a
person, animal, or object from injury or damage. The harness is an attachment
between a stationary and non-stationary object and is usually fabricated from
rope, cable or webbing and locking hardware.
 Use of PPE
• Key point: When hazards in the workplace can't be eliminated or reduced by other risk controls,
employers must provide personal protective equipment and clothing (PPE).

• Employees must be instructed in how to use PPE and clothing provided by the employer. They should be
told why the use of PPE is necessary before they start the particular job for which it has been provided.

• Where PPE is provided, you must use it as you have been instructed to do.

• Employers should make sure that the PPE they purchase complies with the relevant Standard.

• They must make sure that PPE is stored in a clean and fully operational condition, that it can be easily
found when needed and that it is safe from interference and damage.

• PPE should be inspected regularly and before use to make sure it is in good working order. Damaged or
defective PPE must be reported at once. It must be tagged (to prevent its use until it has been repaired),
or thrown away and replaced.
 Lock out, isolation and tagging
• Lock out, isolation and tagging procedures in a work place are designed to protect people and
property from risks arising from machinery or equipment which has been taken 'out of service'
for repair, maintenance or inspection. The significant hazard is often electricity in such cases.

• Before any repair or other work is started, the machinery or equipment to be worked on must
be disconnected from the electricity supply - unless other adequate precautions are taken to
prevent electric shock.
• Before you start work:

• switch off
• isolate circuits
• fix appropriate tags
• test that the electricity supply is isolated
• always test your test instruments.
 First Aid
N.B – First Aid is only meant to be a temporary measure until assistance can be obtained
• First Aid Box – Every Factory and workshop should possess a first aid box.
• Treatment of Cuts – Do not wash the wound, the skin around it can be cleansed with soap and
water. Apply a sterilized dressing as quickly as possible.
• Treatment of Burns – If it is serious, send for an doctor or ambulance as soon as possible. Cover
the wound with a sterilized dressing, do not apply adhesive or ointment.
• Chemical Burns – Flush with cold water immediately and apply sterilized dressing. Use antidote if available.
Alkaline burns are more serious than acid burns and should receive medical attention asap.

Treatment for Electric Shock – An electric shock is cause by the passing of current through the
body. Currents as low as 0.020A have been known to be fatal.
The severity of the shock will depend on the following things:
a)Voltage between “live” metal and earth
b)Moisture content of skin
c)Proximity of the body to effective earth
d)Length of the time of contact.
Speed is Essential in treatment for electric shock – a few minutes delay may
make all the difference between recovery and death.

1. Switch off current before attempting to remove the causality, if this is not
possible, remove him with an insulated material. .e.g. – jacket, dry wood, of dry
news paper Do not attempt to grasp causality's skin

2. Remove any obstructions to breathing .e.g. tight collar or false teeth

3. Commence artificial respiration.